Designer applications can be exported from the designer interface when you are logged in as the systemadmin or any admin level user. To do this, click the Export button when you’re in the designer interface for your web application. This will give you a file with *.des extension. This file contains all information about your web application, including the user interface, database structure, stylesheets, and even the underlying workbook. However, please note that the export file doesn’t contain any records that may have been saved under your web application.
A *.des file can be used to essentially create a copy of your web application in two ways: First is by importing this file into an existing designer application, and second is using this file instead of a workbook when creating a new application.
Only systemadmin user can import a *.des file onto a database enabled application in Legacy SpreadsheetWeb. In Hub, this right is extended to workspace administrator as well.